Who finds parenting the most stressful, and who the least? Judging by the results of three recent studies, the answer hinges partly on the definition of stress.

According to a 2015 study of mothers in Scotland, the least-educated moms experience the most parenting stress, followed by the most highly educated mothers and then those with an intermediate level of education. The study drew on a nationally representative sample of cohort of ten-month-old children, and the measure of parenting stress drew on mothers’ level of agreement with three statements: “Having a child leaves little time and flexibility in my life,” “It is difficult to balance different responsibilities because of my child,” and “Having a child has meant having too few choices and too little control over my life.”

About half of the high- and low-education groups’ elevated stress was attributable to a lack of support, like having less frequent contact with children’s grandparents. The types of support that predicted their stress levels varied somewhat, however. The best-educated mothers’ stress levels were related to greater reliance on formal child care and less frequent communication with friends, presumably due to their more demanding jobs. The least-educated women’s parenting stress, on the other hand, was more strongly linked to having smaller networks of grandparents and friends and facing more barriers to professional parent support. Mothers who were single (without a coresident spouse or partner) and who were immigrants to Scotland also reported greater parenting stress than their partnered and non-migrant counterparts.

Two U.S.-based studies came to different conclusions with regard to education: They found that more parental education means less parenting stress.

A 2010 study that appeared in Child: Care, Health and Development measured parenting stress using four questions (asked of “the adult in the household who was the most knowledgeable about the sampled child’s health and health care”): “During the past month, how often have you felt [child’s name] is much harder to care for than most children [child’s name]’s age?” “During the past month, how often have you felt [child’s name] does things that really bother you a lot?” “During the past month, how often have you felt you are giving up more of your life to meet [child’s name]’s needs than you ever expected?” and “During the past month, how often have you felt angry with [child’s name]?”

The study concluded that 12.6 percent of U.S. kids have at least one parent reporting high parenting stress. Immigrant parents and single mothers again were more likely to experience high levels of stress, as were non-whites, parents with worse mental health, and parents of children with only fair or poor health. Parents in better-educated households were less likely to have high stress levels.

A 2011 Journal of Marriage and Familystudy using a third definition of parenting stress echoed that finding. Researchers Kei Nomaguchi and Susan Brown measured U.S. mothers’ concern related to their toddlers’ “safety when they’re away from you,” “the trouble they might get into,” and “not being sure if you’re doing the right thing for them.” They discovered that after controlling for several demographic and child-related variables, “mothers with some college education, a college degree, or an advanced degree showed less parenting anxiety than mothers with a high school diploma.”

To summarize: It seems that if you define parenting stress in terms of time strain, autonomy, and juggling responsibilities, as in the Scottish study, highly educated mothers will report more stress than the moderately educated. However, if the definition is more about frustration with young children’s behavior and needs, or about elemental child-related concerns and uncertainties, as in the two U.S. studies, better-educated parents feel the least stress. By all three measures, the least-educated parents struggle the most.

But there’s a twist. Nomaguchi and Brown also found that less educated mothers gain more new life meaning from their children: they find “the meaning and purpose your child gives your life,” “passing on to your child what you know,” “being needed by your children,” “the companionship your children provide,” and “the way your children change you for the better” more rewarding than mothers who are college-educated. On top of that, they report less concern over role captivity (“feeling tied down because of the children,” “not having any time for yourself because of the children,” “not being able to spend your time the way you want”). Less educated women are likely to encounter more challenges in raising and supporting their kids than their college-educated peers, but at least according to this study, they also find certain aspects of parenting more rewarding.